Sugarcane: How environmentally sweet it is

Poor Brazil: The country has too much of a good thing in the Amazon Rainforest and the biodiverse plain, called the Cerrado, that adjoins it. With the world watching their every move, the Brazilians tried to go green by using sugarcane to produce ethanol to fuel their cars. It makes a much more energy-efficient ethanol than corn, by the way.

They were too successful. So much sugarcane was used for ethanol that some growers expanded into the Cerrado (bad), forcing cattle ranchers to move into the Amazon (worse).

A new Carnegie Institution study offers the Brazilians a break. Sugarcane, it turns out, actually cools the climate relative to other crops, by reflecting more sunlight back into space and by lowering the temperature of the surrounding air as the plants “exhale” cooler water. When natural vegetation is replaced by sugarcane, however, the result is a rise in temperatures.

Nevertheless, the Carnegie findings carve out a tiny sweet spot for the henpecked Brazilians: If sugarcane crops that go to ethanol are limited to existing cropland, the country can simultaneously mitigate climate change by reducing carbon emissions and adapt to a warmer global climate by keeping local temperatures 1.67 °F cooler.

Here in the U.S., perhaps Hawaii, Florida and Louisiana — which grow sugarcane — could benefit from these findings, too.